1. Field of the Invention
The present invention relates to a starter protector for protecting a starter by preventing the continuous energizing of the starter and by preventing the reactivation of the starter while an engine or the starter is rotating under inertia or while the engine is running.
2. Description of the Related Art
A starter is activated by the action of switching on a start switch of a key switch, whereby an engine is ignited and started. Once the engine is ignited and started, the starter is deactivated by the action of switching off the start switch of the key switch. At that time, if there is any cause for deterioration of the return of the key switch, etc., the start switch may not be switched off and the starter may continue to operate even after the engine has been ignited, causing the starter to generate heat and be damaged by that heat. Also, the engine may not ignite as soon as the start switch of the key switch is switched on and if the start switch of the key switch is switched off once and immediately switched back on, the starter may be reactivated while the engine or the starter is rotating under inertia, or the starter may be activated while the engine is running, and there is a risk that a pinion gear on the starter may be damaged when it tries to engage a ring gear on the engine.
For these reasons, starter protectors are conventionally known which provide the function of preventing the excessive continuous energizing of the starter and the reactivation of the starter while the engine or the starter is rotating under inertia or while the engine is running. As an example of a circuit for such a starter protector, FIG. 4 shows a schematic diagram of a starter activation circuit incorporating a circuit for a starter protector. Examples of constructions of starter protectors incorporating the circuit are shown in FIGS. 5 and 6.
In FIG. 4, the circuit for the starter protector comprises: a circuit for an auxiliary switch 20 having a magnetizing coil 21 and contacts 22 for generally opening and closing a starter main switch; and a regulating circuit 31 for a protector circuit 30 for terminating the energizing of the magnetizing coil 21 of the auxiliary switch 20 under predetermined conditions and opening the auxiliary switch 20. The circuit 31 for a protector circuit 30 may comprise, for example, a timer circuit for terminating the energizing of the magnetizing coil 21 at a predetermined time after the key switch is switched on.
40 is a starter motor which is a direct-current motor for starting the engine; and 50 is a main switch having main contacts 52 for opening and closing the current to the starter motor 40 and a magnetizing coil 51 for opening and closing the main contacts 52. 1 is a power supply battery; and 2 is a start switch disposed in the key switch.
Next, the operation of the starter activation circuit will be explained.
When the start switch 2 is switched on, the magnetizing coil 21 is magnetized and the contacts 22 close. Next, an electric current flows through the magnetizing coil 51 and the starter motor 40 as well, and the pinion gear (not shown) meshes with the ring gear of the engine (not shown). If the pinion gear meshes with the ring gear normally, the main contacts 52 close and main current flows through the main contacts 52 to the starter motor 40 and the engine is started. When the start switch 2 is switched off, the circuit 31 is no longer energized, the contacts 22 open, and the main contacts 52 also open, stopping the operation of the starter motor 40. Also, the energizing of the magnetizing coil 21 is terminated by the circuit 31 after a predetermined time has elapsed from the switching on of the start switch 2, and similarly, the contacts 22 open and the main contacts 52 also open, stopping the operation of the starter motor 40.
FIGS. 5 and 6 are perspective views showing conventional constructions of starter protectors.
In FIG. 5, an auxiliary switch 20 comprises an approximately cylindrical housing 23 and a cap 24 having terminals 24a for wiring to the starter, etc. A mounting bracket 25 for securing the auxiliary switch 20 to the starter is secured by welding to the outer circumferential portion of the housing 23. A cylindrical magnetizing coil 21 (not shown) is disposed coaxial to the housing 23 within the housing 23, and contacts 22 (not shown) are disposed on the cap 24 side of the magnetizing coil 21 in a straight line with the magnetizing coil 21 in the axial direction.
A protector circuit 30 is disposed in a straight line with the auxiliary switch 20 at the opposite end of the auxiliary switch 20 from the cap 24. Lead wires 29 for connection to the circuit within the auxiliary switch 20 are disposed on the protector circuit 30 and extend over the housing 23 of the auxiliary switch 20 to the terminals 24a on the cap 24.
The mounting bracket 25 is a flat plate bent to a cylindrical shape to match the outer circumferential shape of the housing 23 and is secured to the case by welding. Leg portions 25b having flat portions with slots 25a for securing by screws to the starter are disposed at both ends of the mounting bracket 25.
In FIG. 6, the main difference from FIG. 5 is that the protector circuit 30 is built into the cap 24 of the auxiliary circuit 20 which comprises an approximately cylindrical housing 23 and a cap 24 having terminals 24a for wiring to the starter, etc.
A plan view showing a construction of a starter fitted with such a starter protector is shown in FIG. 7. A view from the direction of X in FIG. 7 is shown in FIG. 8.
A starter 60 comprises: an approximately cylindrical starter main body portion 42 having a starter motor 40 within and having flanges 41 for mounting the starter 60 on an engine (not shown); and a main switch portion 51 disposed alongside the starter main body portion having an approximately cylindrical shape smaller than the starter main body portion and having a main switch 50 within. The starter protector shown in FIG. 6 is secured by screws 11 to flange surfaces 55 disposed on the main switch portion 51. A space 27, which is dead space, is formed among the housing 23 and the mounting bracket 25 of the auxiliary switch 20 of the starter protector and the flange surfaces 55.
Starter protectors having the above construction are long in the axial direction of the starter protector and require a lot of space to mount the starter protector onto the starter. Consequently, there are a lot of restrictions on where the starter protector can be mounted onto the periphery of the starter and sometimes it is difficult to fit the starter protector directly onto the starter.